This invention relates to an electric motor unit and an electronic control of the motor.
The electric motor unit proposed by the invention can be advantageously used in a motorized fan used for the heater and/or vent and/or air conditioner of a motor vehicle.
Historically, the stator of such a motor unit comprises a carbon holder plate (PPC) which includes a brass insert and a radiator.
The brass insert serves to guide the carbon holders and to bring the current closer to the foot of the MOSFET of the power circuit near the radiator.
The radiator, generally made of aluminum, provides cooling to the power components (diodes, MOSFET transistors) and provides a space into which several electronic components on a circuit board that has been imprinted with the control electronics are received and held.
A motor unit of this type was described in the French patent application that the Assignee filed under number 98 03128.
One aspect of the invention is that a motor unit structure provides for very high mounting tolerances between the radiator and the brass insert.
In another aspect of the invention, the rigidity and the watertightness of a motor unit structure has been improved.
It is a further aspect of the invention to provide a motor unit structure of which the means for connecting and the assembly of the components are simplified.
The present invention provides an electric motor unit of a motor vehicle having a brush carrier plate that includes a brass insert and a radiator, characterized by the plate having a plastic over-molding that surrounds the insert and the radiator. This over-molding provides make up for play between the parts.
Furthermore, the over-molding contributes to the rigidity of the plate, which allows optimization of the design of the radiator and the quantity of aluminum used for it, by removing from the radiator the parts that are not necessary for cooling and that only serve to increase the rigidity of the plate. Moreover, the over-molding also includes a partition that separates, in a watertight way, on the plate, the area designed to receive the electronic card and an area carrying the brushes.
The area that is delimited for the over-molding and which receives the card can furthermore be closed by a lid for which the edge of the over-molding defines a watertight plane.
The system of the over-molding and the lid defines, for the imprinted circuit card and the electronic components (in the cold area of the motor) a watertight housing in which the components are thermically isolated with respect to the area that carries the brushes (electrotechnical areaxe2x80x94hot area). There is also a decoupling between the electronic area and the electrotechnical area.
The separation partition can advantageously provide means for respiration allowing circulation of air from one area to the other without allowing moisture in the electronic area.